According to reports, the common folic acid available on the market is synthetic. After entering the body, it relies on the MTHFR enzyme to be converted into 5-methyltetrahydrofolate before it can be truly utilized by cells. If the MTHFR gene is mutated, enzyme activity decreases. Data show that the C677T mutation reduces enzyme activity to 30%–70% of normal levels, and with double mutations, activity drops even further. The carrier rate for this gene mutation in the Chinese population is 25%–40%, meaning approximately one in four Chinese people carries this genetic variation.

When the synthetic folic acid taken exceeds the liver's conversion capacity, the excess cannot be transformed into active folate and remains in the body as unmetabolized folic acid (UMFA). Studies suggest that supplementing with more than 200 micrograms of synthetic folic acid per day may lead to elevated UMFA levels in the blood, which could mask vitamin B12 deficiency symptoms and interfere with zinc absorption. Associated health risks are still under ongoing investigation.

Homocysteine (Hcy) is a key indicator of folate metabolism. Poor folate metabolism directly causes the accumulation of homocysteine in the blood. Relevant reports show that about 40% of Chinese residents have hyperhomocysteinemia. Elevated Hcy levels multiply the risk of cardiovascular disease and are a major risk factor for stroke. For people with MTHFR gene mutations, simply taking ordinary folic acid makes it difficult to effectively lower homocysteine levels.

To address the conversion barrier caused by genetic factors, 5-methyltetrahydrofolate calcium – also known as active folate – does not require MTHFR enzyme conversion and can be directly absorbed and utilized by the body, unaffected by gene mutations and without producing unmetabolized folic acid. In 2017, China approved 5-methyltetrahydrofolate calcium as a new food nutrition fortification ingredient, permitting its use in special dietary foods.

Key groups that should pay attention to folate metabolism include: women preparing for pregnancy or currently pregnant, middle-aged and older adults with hypertension, carriers of MTHFR gene mutations, and men planning to conceive.

Medical experts advise that folate itself is essential to human health, and ordinary folic acid remains safe and effective for the majority of people. However, supplementing nutrients does not guarantee that the body can absorb and utilize them. The public is encouraged to consider their genetic profile and homocysteine test results, and under the guidance of a qualified physician, choose a folic acid supplementation plan that suits their individual needs – ensuring scientifically sound and rational nutrient intake.

(This article is a popular science news release and does not constitute medical advice. For health concerns, please consult a healthcare professional.)